Medical instruments with a shaft that is rotatable about its longitudinal axis are known in practice in particular in instruments having an at least partially curved shaft.
In these known instruments, the shaft is fixed by frictional engagement or form-fit engagement. The fixing arrangements by form-fit engagement, where shaped parts corresponding to one another engage in one another, generally have only a small number of adjustment steps.
Although the fixing of the shaft by frictional engagement has the advantage that the shaft can be rotated steplessly, this type of fixing also has the disadvantages that, on the one hand, a relatively high force has to be applied in order to clamp the component parts firmly against each other and, on the other hand, the fixing by frictional engagement is very susceptible to wear and, in addition, can have functional problems in the presence of moisture.
Proceeding from this, the problem addressed by the invention is that of designing a medical instrument with a shaft rotatable about its axis in such a way that this instrument, while being easy to handle, permits a large number of secure and positionally precise rotations of the shaft with respect to the handle, but at the same time takes up the least possible space.